Circuit interrupter



May 7, 1940. A. H. BAKKl-:N

CIRCUIT INTERRUPTER Original Filed Sept. 2l. 1938 3 Sheets-Sheet 1 o WITNESSES: WMM

Wiz@ Maw May 7, 1940. A. H. BAKKEN CIRCUIT INTERRUPTER Original Filed Sept. 21, 1938 3 Sheets-Sheet 2 /4/1 f/f /f/ f f f f v/////// //ff/ f//f//f/ y I INVENToR WITNESSES:

May 7, 1940. A. H. BAKKEN CIRCUIT INTERRUPTER original Filed sept. y21. 1958 3 Sheets-Sheet 5 lNVENTOR Aliczvewabwf.

BY W W Patented May 7, 1940 UNITEDl sTATEs CIRCUIT INTEBBUPTEB Andrew 11. Bakken, Edgewood, Pa., signor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation ot Pennsylvania Application september 21, 193s, serial No. 230,948 Renewed November 15, 1939 18 Claims.

This invention relates to high-voltage, highpower circuit interrupters and more particularly to improvements in the housing structures therefor. Arc extinction in high-power circuit inters rupters of either the gas blast or liquid immersed type is accompanied by the generation of arc gases in quantities which cause considerable pressure within the interrupter housing. During the interruption of extremely severe short circuits or short circuits of lesser magnitude, but of considerable duration, the pressure produced may exceed the safe limits of the housing in that inadequate means, in the form of a breather or muffler. are provided to relieve the pressure. The proviu sion of pressure relieving means, in addition to the conventional breather or muier, is of particular importance in breakers of the porcelain-clad type, wherein the housing structure is composed largely of insulating material and, therefore, more subject to failure as a result of high pressure during arc extinction.

The present invention has for its object the provision of a circuit breaker housing which is capable of quickly relieving the pressure generated therein even during the interruption of sustained short circuit currents of extremely large magnitude.

A further object of my invention is the provision of a circuit breaker in which the relief of a. pressure is controlled by the same resilient means which is utilized in moving the breaker contact structure to the open circuit position, but which is independent of the breaker contact position.

Other objects and advantages will appear more fully in the following description when taken in connection with the accompanying drawings, in which:

Figure 1 is a side view, partially in section, of

a circuit breaker illustrating an embodiment of o my invention;

Fig. 2 is a sectional view of the upper portion of the circuit breaker of Fig. 1 on a larger scale, showing the interrupter in the closed circuit position and the pressure relieving structure in its u normal position;

Fig. 3 is a sectional view similar to Fig. 2 showingthe interrupter in the open circuit position and the pressure relieving structure in the operative position;

Fig. 4 is a cross-sectional view of the interrupter shown in Fig. 2 taken along the line IV-IV;

Fig. 5 is a cross-sectional view of the interrupter shown in Fig. 2 taken along the line V--V;

u and (Cl. 20o-150) Fig. 6 is an exploded perspective view of the linkage mechanism utilized in operatively coupling the pressure releasing cap of the breaker housing with the main operating spring of the breaker.

Referring to the drawings, the reference numeral I0 designates a metallic casing having a top support plate I2 which carries a tubular insulator I4 of porcelain or other weatherproof insulating material. 'I'he upper end of the insulator I4 has an annular metallic plate I6 seated thereon which carries a dome-like closure comprising a cylindrical metallic section I8 and a cap-like metallic member 20. The cap member 20 is yieldingly maintained in position with respect to the cylindrical section I8 in a manner and for a purpose which will be more fully described hereinafter.

Disposed within the tubular insulator I4 is a tubular support and strain member 22 of insulating material having a metallic collar 24 secured to each end thereof. The lower collar 24 in cooperation with bolts 26 serves to rigidly secure the strain member 22 to the supporting plate I2. The upper collar member 24 is secured by bolts 28 to an annular support plate 30, which in turn is bolted to the annular plate I6. The relative lengths of the tubular insulator I4 and the tubular strain member 22 are such that when the securing bolts 28 are drawn towards clamping engagement with the upper collar 24, the strain member 22 will be placed in tension, and the tubular insulator I4 will be placed in compression. The strain member 22, in that it is securely fastened at its lower end to the support plate I2, also carries all lateral stress which may be placed upon the interrupter housing, thereby relieving the external insulator I4 of all stresses except those which arise in compression.

A circuit interrupting unit generally shown at 32 is disposed within the tubular strain member 22 and consists of two interrupting elements 34 and 36 arranged for series operation. The upper end of the interrupting element 34 is provided with a flanged metallic casing 38 having four laterally extending support arms 4I). The support arms 40 provide the sole support for the interrupting unit 32, and are adapted to be secured to the support plate 30 by means of bolts 42 as shown. 'I'hus the entire interrupting unit may be removed from the interrupter housing by merely removing the four bolts 42.

The circuit interrupting unit 32 and the method of mounting the same with respect to the interrupter housing are clearly shown and describedy in the oopending application of B. P. Baker, Serial No. 230.946, nled September 2i, 1938, and assigned to the assignee of this application.

' g As shown and described in the aforesaid application and in Figs. 2 and 3 of the instant application, the interrupting element 84 comprises an outer casing 44 of insulating material having a plurality oi' washers 48 and 48 oi' diierent inl. ternai diameter alternately disposed in the lower end thereof. so as to form a corrugated are chamber48. Theupperendofthecasinguinconjunction with the flanged casing member 88 form an expansion chamber 88 in which are disposed a u plurality of nxed contact nngers 82. 'Ihe contact fingers 82 are connected by means ot flexible shunts 84 to the iianged casing member 88.

A movable operating member 88 extends axial- 1y through the arc chamber 48 and the expansion l chamber 88, and is provided with a contact ring 88 adapted to engage the nxed contact tingers 82 when in the closed position. as shown in Fig. 2. 'Ihe operating member 88 also carries a plurality oi' washers 88 and 8i of different diameters 8l and which are alternately disposed so as to form a corrugated section of insulating material which serves as a follow-up member for restricting and limiting the dimensions ot the arc chamber 48 when the operaitng member is moved to the open 88 circuit position.

'I'he construction and arrangement oi the interrupting element 88 is similar to that of the element 84 above described. 'I'he movable elements oi the interrupter 88, such as the contact u ring 88 and the corrugated section of insulating material, are also carried by the operating member 88.

A series connection between the elements 84 and 88 is effected by a conducting sleeve 81 cardo ried by the operating member 88, which sleeve joins the contact ring I8 of the element 84 and is, in turn, connected to the contact fingers 52 of the interrupting element 88 by ilexible shunts 88. An external circuit connection. is made to 48 the upper end of the interrupting unit 82 by means oi a ilexible connector 88 ioining the iianged casing 88 and a line terminal ,88 passing through the side of the cylindrical casing I8. A line terminal 81 extending through the casing I8 88 and connected by a exible connector 88 to the lower end of the operating member 88 provides the external circuit connection to the other end of the interrupting unit 82. 'I'hus the electrical circuit through the interrupter proceeds from the 88 upper line terminal 88 through the connector 88 to the ilanged casing 88, the flexible shunts 84, the contact nngers 82, the movable contact ring 88. the conducting sleeve 81, the flexible shunts 88 and then through the contact fingers and the 80 contact ring of the interrupting element 88, the

lower end of the operating member 88, the connection 88, and terminates at the line terminal 81.

It will be noted that the contact ring 88 adjacent the left-hand contact ilnger 82, as shown 88 in Fig. 2, is extended outwardly and has considerably greater width than the portion adjacent the right-hand contact ilnger 82. This arrangement, during the opening operation of the interrupter, causes the left-hand contact nger 82 70 to separate last in point of time irom the contact ring 88, thereby causing the arc to be drawn between the left-hand contact nnger 82 longitudinally of the arc chamber 48, and to be coniined in the comparatively narrow passage ben tween the iixed washers 48 and 48 and the movablewashera88and8l carriedbytheoperating member I8.

rhs downward movement oi' the operating member 88 to the open circuit position, as shown inFig.3,alsocausesa iiowof arcextinguishing 8 liquid longitudinally o! the arc to bring about `arc extinction in a manner more fully described in the aforesaid application. Movement of the operating member 88 to the open circuit position is ei'iected by a battery of compression springs 88 i8 arranged in the dome-like closure of the casing! I8 and 28. The springs 82 are disposed between an upper pressure plate 84 and a lower pressure plate 88, each ci' which are guided for reciprocating movement upon the guide and support rods 1| 88, the lower ends ot which are respectively secured to the tour supporting arms 48 carried by the hanged casing 88. The upper ends oi the guide rods 88 are united with a stop plate 18 towards which the pressure plate 84 is urged by l the springs 82. 'I'he lower pressure plate 88 is secured to the upper end of the operating member I8. The operating member 88 is moved to the closed circuit position against the tension oi' the springs 82 by a suitable straight-line operat- I ing mechanism generally indicated at 12 disposed in the casing I8. Upon release of the operating member 88 by the operating mechanism 12, the compression springs 82 drive the prsure plate 88 and the operating member 88 l downwardly to the open circuit position, thereby establishing an arc in each oi' the arc chambers 48 and bringing about circuit interruption.

The circuit interrupting elements 84 and 88 are provided with a vent opening 14 for the I escape oi' the products oi' decomposition oi the arcs drawn therein into the space within the tubular strain member 22 and the dome-like closure thereabove. In the event that the arcing is severe or unduly prolonged. considerable go pressure is generated within the tubular strain member 22. In order to relieve the interrupter housing oi' abnormal pressure. provision is made for resiliently supporting the cap member 28 upon the cylindrical closure member I8, whereliry'4 a the cap member 28 will he raised suillciently to permit Vgas and arc extinguishing liquid to escape betwgn the separating edges of the sections I8 and The mechanism ior maintaining the cap memn ber 28 in position with respect to the cylindrical section I8 comprises a bolt 18 passing through a metallic bushing 18 secured to the upper end of the cap member 28. 'Ihe lower end of the bolt 18 has a square head 88, and is adapted to ilt in gg a square recess 82 provided in the stop plate 18. Surrounding the bolt 18 and secured to the stop plate 18 is a box-like support 84. the four sides of which respectively parallel the four sides in the square aperture 82. Each side of the supn port 84 is provided with a rectangular aperture 88 adjacent the stop plate 18 for the reception of a lever 88. The inner ends oi' the levers 88 are adapted to rest upon the shoulders of the square head 88 of the bolt 18. The outerends of the el levers 88 are provided with a conical recess 88 into which the ends of pivotal bolts 82 are seated. The bolts 82 are supported by and screw threaded through the moving pressure plate 84, and are provided with lock nuts 84 for the pur- 78 pose o! locking the bolts in position with respect to the pressure plate 84 when the proper adjustment has been made.

From the foregoing description it is apparent that the mechanism for holding the cap member fl arcano? 2l into engagement with the cylindrical section Il constitutes a simple lever arrangemenhthe operation oi which is as follows:- The holding bolt 'It is placed imder tension by means of a nut screw threaded on the upper end thereof -soastocause thehead lltoraisetheinnerends oi' the levers I8 against the upper edge oi the apertures 0B in the box-like support Il. This causes the outer ends of the levers Il to move downwardly and exert a force upon the pivotal support bolts 92. Since the pivotal support bolts l2 are carried by the movable pressure plate M, which, in turn, is engaged by the compression springs 62, the compression springs will oppose the force exerted by the tension in the bolt I6 to resiliently hold the cap member 20 in engagement with the cylindrical section IB. Thus in the event that the pressure within the interrupter housing exceeds a predetermined value, the cap member 20 will be raised from its seat upon the cylindrical section I8 against the compressive action oi the springs 62. Inasmuch as the pressure plate El engages the upper end of the spring 62, the springs 62 may be utilized for resiliently holding the cap member 20 in position independently of the position of the lower movable pressure plate 66 and the operating member 56.' In other words, the compression springs 62 constantly exert a biasing force for maintaining the cap 20 in position irrespective of the position of the operating member 56. The pressure acting upon the cap member 20 during circuit opening operation also reacts to cause the upper pressure plate 6l to move downwardly so as to increase the force tending to move the operating member 56 to the open circuit position. In order that the cap member will automatically align itself with respect to the cylindrical section I8, the lower end of the cap member is provided with a conically flanged seat surface 98, as shown in Figs. 1 to 3 of the drawings.

Although I have shown and described a specific circuit breaker structure, it is to be understood that the same is for the purpose of illustration and that changes and modications may be made by those skilled in the art without departing from the spirit and scope of the appended claims.

I claim as my invention:

1. In a circuit interrupter, a housing, circuit interrupting means within said housing, said circuit interrupting means including a pair of contacts at least one of which is movable for establishing an arc, resilient means for biasing said movable contact to the open circuit position, and pressure relieving means associated with said `housing including a member movable to open and closed positions, said movable member being normally biased to the closed position by said resilient means and moved to the open position in response to predetermined pressure conditions within said housing.

2. In a circuit interrupter, a housing including two separable sections, resilient means for normally holding said separable sections together, separable contacts within said housing, and actuating means including said resilient means for operating said contacts to the open circuit position to establish an arc, said resilient means enabling said separable sections of said housing to move apart in response to predetermined pressure conditions within said housing.

3. In a circuit interrupter, a housing having a vent opening, a closure member for said opening movable to open and closed positions, spring means biasing said closure member to the closed position, contact means within said housing. and an actuating including said spring means for operating said contact means to establish an arc within said housing, said closure member being movable to the open position against the bias o! said spring means in response to predetermined pressureconditions set up by said arc.

4. In a circuit interrupter, a housing including two separable sections, a pair of contacts within said housing one of which is movable .for establishing an arc, and a spring arranged for independently actuating said movable contact to the open circuit position and resiliently holding said separable sections together.

5. In a circuit interrupter, a housing including a releasable closure member, a pair of contacts within said housing at least one of which is movable, an actuating member for said movable contact. a compression spring for driving said actuating member to the open circuit position to establish an arc, and a` linkage mechanism operatively. coupling said compression spring with said releasable closure to cause said spring to bias said closure into engagement with said housing independently of the position of said actuating member.

6. In a circuit interrupter, a housing including a releasable closure member, a pair of contacts Within said housing at least one of which is movable, an operating member for said movable contact, actuating means including a compression spring, a spring support having a pair of movable plate members between which said spring is disposed, means operatively coupling one of said plate members to said contact operating member fork biasing said movable contact to the open circuit position, and means operatively coupling the other plate member to said releasable closure for biasing said closure toward said housing.

7. In a circuit interrupter, a vertically disposed tubular housing, a releasable cap member seated upon the upper end of said housing, separable contacts within said housing, actuating means including a spring for operating said contacts to the open circuit position, and a linkage operatively coupling said spring with said cap member for biasing the latter toward said housing, said cap member being adapted to be raised from its seat against the bias of said spring in response to predetermined pressure conditions within said housing for quickly relieving the housing of said conditions.

8. In a circuit interrupter, a vertically disposed tubular housing, a releasable cap member seated upon the upper end of said housing, separable contacts Within said housing, actuating means including a spring for operating said contacts to the open circuit position, and a linkage operatively coupling said spring with said cap member for biasing the latter toward said housing, said cap member being adapted to be raised from its seat against the bias of said spring in response to predetermined pressure conditions within said housing for quickly relieving the housing of said conditions, said cap member having a conically flanged seat surface for automatically aligning the cap member with said housing upon the subsidance of pressure within said housing.

9.' In a circuit interrupter, a housing containing arc-extinguishing liquid, circuit interrupting means within said housing including separable contacts for establishing an arc, liquid moving 1g means operative for subjecting the arc path between said contacts 'to a ow oi arc extinguishing liquid, resilient means for actuating said liquid moving means and pressure relieving means associated with said housing including a member movable to open and closed positions, said movable member being normally biased to the closed position by said resilient means and moved to the open position in response to predetermined pressure conditions within said housing.

10. In a circuit interrupter, a housing containing arc-extinguishing liquid, said housing having two separable sections, separable contacts within said housing for establishing an arc, liquid moving means operative to establish a ow of arc-extinguishing liquid in the arc path between said contacts and resilient means arranged for actuating said liquid moving means and resiliently holding said separable sections together.

11. Inl a circuit interrupter, a housing containing ero-extinguishing liquid, said housing having two separable sections, separable contacts at least one of which is movable for establishing an arc, a plunger member movable with said movable contact for subjecting the arc to a flow of arc-extinguishing liquid, and spring means arranged ior independently actuating said plunger member and resiliently holding said separable sections together.

12. In a circuit interrupter, a housing containing arc extinguishing liquid and having a vent opening, a closure member for said opening movable to open and closed positions, separable contacts for establishing an arc within said arc, extinguishing liquid, liquid moving means operative to cause a ilow of arc extinguishing liquid in the path between said contacts, and spring means for biasing said closure member to the closed position and for actuating said liquid moving means, said closure member being movable to the open position against the bias of said spring means in response to predetermined pressure conditions set up by said arc.

13. In a circuit interrupter, a housing including a releasable closure member, arc extinguishing liquid in said housing, a pair of contacts within said housing, at least one of which is movable to establish an arc, a piston member carrying said movable contact and operative to move arcextinguishing liquid into engagement with said arc, spring means to operate said piston member to open circuit position and a linkage mechanism operatively coupling said spring means with said releasable closure to cause said spring means to bias said closure into engagement with said housing independently of the position of said piston member.

14. In a circuit interrupter, a housing containing arc extinguishing liquid and having a releasable closure member, separable contacts within the housing for establishing an arc within said arc extinguishing liquid, liquid moving means operative to establish a ow of arc extinguishing liquid between said contacts, actuating means including a compression spring for amano? operating said liquid moving means, a spring support having a pair oi movable plate members between wnicn said spring is disposed, means operatively coupling one ol said plate members to said liquid moving means and means operatively coupling me other plate member to said releasable closure member lor biasing said closure member toward said housing.

lb. ln a circuit interrupter, a vertically disposed tubular housing, a releasable cap member seated on the upper end oi' said housing, a quantity of arc extinguishing liquid in said housing, separable contacts immersed in said arc extinguishing liquid for establishing an arc, a piston member operative to move arc extinguishing liquid between said contacts, spring means for operating said piston member and a linkage operatively coupling said spring means with said cap member for biasing the latter toward said housing, said cap member being adapted to be raised from its seat against the bias ot said spring means in response to predetermined pressure conditions within said housing for quickly relieving the housing of said conditions.

16. In a circuit interrupter, a housing containing arc-extinguishing liquid, circuit interrupting means within said housing including separable contacts, at least one oi' which is movable for establlshing an arc, liquid moving means operative for subjecting the arc path to a flow of arc-extinguishing liquid, pressure relieving means for said housing including a member movable to open and closed positions and single resilient means for actuating said movable contact and said liquid moving means and for biasing said movable member to the closed position against the pressure within said housing.

17. In a circuit interrupter, a housing including two separable sections, arc extinguishing liquid in said housing, a circuit interrupting means including separable contacts immersed in said arc extinguishing liquid, at least one of said contacts being movable for establishing an arc, liquid movingmeans operative for subjecting the arc path to a ilow of arc extinguishing liquid, and a single resilient means for actuating said contact and said liquid moving means and for resiliently holding said separable sections together.

18. In a circuit interrupter, a vertically disposed tubular housing, a releasable cap member seated on the upper end of said housing, a quantity of arc extinguishing liquid in said housing, separable contacts immersed in said arc extinguishing liquid at least one of said contacts being movable to establish an arc, a piston member operative for subjecting the arc path to a now of arc extinguishing liquid, a spring means for operating said movable contact to open circuit position and for actuating said piston member, and a linkage operatively coupling said spring means with said cap member whereby said spring means biases said cap member toward said housing independently oi' the positions of said movable contact and piston member.

ANDREW H. BAKKEN. 

